Fuse-plug type circuit breaker



Oct. 13, 1936. 1 GE|5S| |NGER 2,057,093

FUSE PLUG TYPE CIRCUIT BREAKER Filed July 6, 1935 5 70 j! ATTORNEYPatented oct. 13, 1936 PATENT .OFI-ICE FUSE-PLUG BREAKEB JohnGeisslingenlamaica, N. Y., assigner to Die Cast da Forge Corporation,New York, N. Y., a corporation of New York Application July 6, 1935,Serial N o. 30,062

17 Claims.

This invention relates to a fuse-plug type of circuit breaker; thatis-to say, a circuit breaker built in the form of and substantially thesame size as the present standard fuse-plugs, whereby such fuse-plugsmay be replaced by one of the circuit breakers herein disclosed.

' The fuse-plugs used in cut-out panels or boxes in buildings,particularly, homes, have become standardized as to mechanicaldimensions, and to l0 make an automatic circuit breakerwhich will fit inthe same socket as a standard fuse-plug, presents a real problem, butthe advantages of such a fuse-plug type of circuit breaker are several.

It frequently happens. in the operation of electric fiat irons, washingmachines and other laborsaving devices now used in the homes, that shortcircuits or overloads occur which very frequently blow out the fuses,with the result of annoyance to the worker, who is usually inexperiencedin the matter of testing to see what fuse or fuses have become disabled,and in the replacement of these devices. In most cases, it happens thatno extra fuses are at hand and so the proper size may not be apparent tothe one who is to replace the fuse. g5 Hence, an automatic circuitbreaker, which is self-indicating and which any one can restore, andwhich will t in the place of the present standard fuse-plugs, is adecided advantage, assuming of course that the circuit breaker ispositive and reliable in its operation.

It is the principal object of my invention to provide a reliable,self-indicating and automatic,

fuse-plug type of circuit breaker to take the place of the presentfuse-plugs.

While obtaining this advantage, all the other advantages which flowtherefrom will appear to most anyone, after reading the specificationtaken in connection with the annexed drawing, wherein:

Figure 1 is a sectional elevation on a much enlarged scale of one formof my device.

Figure 2 is a view looking down on the switchplate and parts with thecap removed.

Figure 3 is a bottom view of the switch-plate shown in Figure 2.

Figure 4 is a diagrammatic illustration of the circuit arrangementinvolved in my device.

Figure 5 is a view similar to Figure l, showing my preferred form ofstructure.

Figure 6 is a view substantially full-size of the w interior of the plugbase, with the switch-plate removed, showing two of the contact membersutilized for completing a circuit through the` circuit breaker.

In the various views, wherein like numbers refer to corresponding parts,I is a base member (Cl. 2ND-48) having an integral stem 2 and cap 3preferably of strong insulating material. The stem 2 carries a metallicshell 4 having the usual formed threads thereon for tting the threads ina fuse-plug socket. The stem 2 also carries a centrally lo- 5 catedcylindrical contact member 5, within which and adjacent the contact endis a core-piece 6. On the other end of the cylindrical member 5, is

a plug 1 of magnetic material having a flange 8 preferably fitting overthe end of a cylindrical 10 shell 3 positioned Within the innerperiphery of the stem 2. Located between the shell 9 and the member 5,is a pair of windings ID and II. The illustrations in the drawing aremerely to show the difference of the windings, without reference to 15the size or the number of turns, it being kept in mind, however, thatthe windings are arranged differentially and in proportion to producethe results which will be hereinafter referred to.

Carried within the base I, is a plate I2 pref- 20 erably of goodinsulating material. Mounted on the plate I2, is a spring I3 which, asshown in Figure 2, is V-shaped, having arms Il and I5 fastened to theplate I in any satisfactory manner as by studs or rivets I6 and I1. Onthe bottom side of the plate I2, the stud I6 carries a contact I3 ofsuitable material, which contact is normally in engagement with acontact I9 carried ona strip 2D made of thermostatic metal. The oppositeend of the strip 20 from the contact I3 is 30 fastened by a stud 2I tothe plate I2, and this stud end is in contact with a spring contactmember 22 carried on the base portion and connected to one end of thewinding I I. The spring I3 carries a contact 22 of suitable material,which is 35 adapted to operate with a contact 24 carried on a spring 25.The spring 25 is bowed at 25 and the bowed end passes through a slot inthe edge of the plate I2 and is preferably fastened on the lower side ofthe plate I2, as shown in Figure 1. Furthermore, this end of the spring25 is connected by a suitable connector 21 to the shell 4 of the plug.

Pivotally mounted at 25 on the plate I2, is a lever having one arm 29extending upwardly and 45 terminating in a catch 30 adapted to engagethe free en d of the spring 25. 'I'he other arm 3| of the catch leverextends over the axial center of the plug so as to be engaged by the end32, preferably of insulating material, of a lever-actuating member inthe form of a pin 33, which pin is located in a hole in the plug 1 andextends into the path of movement of the core-piece 5. The stud I1 isadapted to engage a spring contact member 3l that connects with one endof the winding III. 55

It will be noted from Figure 4. that the windings I0 and II have acommon Junction point which is connected to the central contact memberl.

loosely carried by the spring 2l, is a push button 38 having a stem 3lwhich passes througha large clearance hole in the spring 2l. The stem 30is threaded to receive an adjusting means in the form of a nut 31,whereby the location of the stem 36 with respect to the spring 2! may beadjusted. If desired, an additional nut may be used to lock against thenut 31. The button 35 extends through an opening in the cap 3 and ispreferably red in color or colored red so as to give a visual indicationof the position of the breaker spring 2B. I'he stem 38 is preferablymade long enough so that it will contact with the spring I3 to assist inpushing this spring downwardly when the circuit breaker is reset, itbeing understood that after the catch 30 is engaged by the spring 2l,the button 3l will be held loosely in the spring 25 so that the stem 30is free from the spring I3, allowing the contacts 23 and` 24 to makepositive engagement. l

In order to insure quicker separation of the contacts 23 and 24 at thetime the catch 30 is withdrawn, I provide an auxiliary lever 30 pivotedat 39 on the plate I2, one end 40 of the lever 30 extending intoengagement with a slot in the turned down end of the spring I3. Theother end of the lever 38 preferably rests on a button 4I, preferably ofinsulating material, carried on the arm 3i of the catch lever, both endsof these levers being in the path of movement of the pin 33. Hence, whenthe pin 33 is raised, it trips the catch lever from the spring 25 whichhas considerable tension due to the bow 28 therein. At the same time,the lever 30 is operated so as to produce a quick pull downwardly on theend of the spring I3. Thus, two opposite forces are applied to pull thecontacts 23 and 24 apart, with the result that the breaker contactsseparate rapidly and the arrangement is such that these contactsseparate, as will be seen from Figures l and 5, to a considerabledistance; for example, in plugs that I have made, this distanceapproximates three eighths of an inch.

I have heretofore stated that the windings I0 and II are arrangeddifferentially and in proportion with respect to the number of turns toproduce the necessary results. Further in this connection it may be saidthat the number of turns and size of wire for the windings I0 and Il aresuch that, for a momentary overload, such as might be caused from theoperation of a washing machine or an electric ironer, or electric flatiron,l or a light and brief short circuit, the circuit breaker will notoperate by reason of the difference in the amount of flux produced bythe windings I0 and Il; but should a heavy short circuit be broughtabout, then this heavier current passing through the winding I 0 willoverpower the effect of the winding II and will immediately actuate thebreaker to open the contacts 23 and 24.

On the other hand, if the momentary overload heretofore referred tocontinues for a short period of time. the thermostat 20 will function toopen the contacts 23 and 24, allowing the winding I0 to have its fulleiIect to open the circuit breaker as has been described. It is to beunderstood, as the drawing indicates, that the core piece 6 is separatedfrom the plug 1 by a substantial air gap, so the core piece 3 will bemoving rapidly as it approaches the end of the plug 1, thereby causing arapid movement oi' the catch lever 30 and the auxiliary lever 3l,producing an instantaneous separation of the breaker contacts 2t and 24.As has been heretofore indicated. as the spring 2l moves to openposition, the indicating and restoring button 3B moves outwardly throughthe opening in the cap 3, giving a visual indication that thisparticular circuit breaker has been operated. Thebreakermaybereadilyre'setbymerelypushing inwardly on the button 3l. Ifthe short circuit is still on the line. the circuit breaker will betripped again.

Even with the arrangemmt shown in Figure l, I have produced a circuitbreaker which has withstood a most severe test. Por example. it has beentested on a 13o-volt circuit having a capacity of 10,000 amperes, byclosing a short circuit by means of a.k switch through the circuitbreaker made according to Figure l. and the breaker successfully openedthe circuit without damage to itself.

I have thus produced, in the device herein shown and described, afuse-plug type of circuit breaker, which is positive in its action andwhich can be used in the same places as the standard fuse-plugs nowused.

Certain of the details entering into my construction may be changedsomewhat without departing from the spirit of my invention or the scopeof the appended claims. f

What I claim is:

1. A fuse-plug type circuit breaker including, base and stern portions,the stem having a centrally located contact member and an exteriormetallic screw-threaded shell to engage a cooperative socket. said stemcarrying interiorly thereof a pair of windings surrounding a movablecore piece, said windings being Joined at one point and this junctionconnected to said centrally located contact member, a lever-operatingmember positioned in the path of movement of said core piece, theremaining ends of said windings being connected to contact memberswithin the base portion, a plate carried by the base, said platecarrying a pair of breaker springs having cooperative contacts and athermostat element carrying a contact and connected through one of saidbase contact members to the end of one of said windings, a contact onsaid plate for cooperation with the thermostat element contact andelectrically connected to the other of said remaining winding endsthrough one of said base contacts, and also connected to one of saidsprings on said plate, the other of said plate springs being connectedto said threaded shell, a lever on said plate having one end extendinginto the path of movement of said lever-operating member, the other endof the said lever having a catch thereon to engage the end of the secondof said springs on the plate, a cap for the base, and resetting meanslocated by the cap to move the last-mentioned spring into contactengagement with the first-mentioned spring.

2. A fuse-plug type circuit breaker as set forth in claim l, furthercharacterized in that the breaker springs are positioned on the cap sideof said plate and the resetting means comprises a button located in ahole in the top of the cap and having a stem extending loosely through ahole in the spring engaged by the lever catch, said stem having aretaining and locating device thereon.

3. A fuse-plug type circuit breaker as s et forth in claim l, furthercharacterized in that the thermostat consists of a bi-metallic stripmounted on the side of said plate opposite to said breaker springs, andconstructed so as to open the contacts in its circuit on continued nowof current therethrough.

4. A fuse-plug type circuit breakras setv forth in claim 1, furthercharacterized in'thatone of being mounted on the plate between the armsof said V and being formed in a loop over the V springs, its free endbeing engaged by saidl lever catch.

5. A fuse-plug type circuit breaker as set forth in claim 1, further.characterized in that the said windings are so electrically proportioneda'nd differentially connected that for short time overloads the circuitbreaker will not open but the thermostat will open the winding in itscircuit if the overload continues. allowing the other winding to actuatesaid core piece to separate the breaker springs.

6. A fuse-plug type circuit breaker as set forth in claim l, furthercharacterized in that a second lever is located so one end thereof isactuated by said lever-operating member, while the other end of saidsecond lever engages one of said breaker springs so as to pull thespring away from its cooperative spring when the same is released bysaid catch.

7. A fuse-plug type circuit breaker including, base and stem portions,the stem having contact members to engage cooperative members in asocket, a pair of diherentially connected windings housed within thestem and a junction of said winding being connected to one of the plugcontact members, a movable core piece embraced by said windings, anoperating member in the path of movement of said core piece, a platecarried by said base, a pair of breaker springs mounted on the plate butinsulated from each other and each carrying cooperative contacts, a capfor the base, a resetting button having a stem adjustably engaging oneof said springs, the button protruding through the cap and the springbeing connected to one of the plug contact members, a lever having acatch to engage the end of the last-mentioned spring, the opposite endof the .lever extending into the path of movement of saidlever-operating member, a thermostat device carried by said plate andhaving contacts connected into circuit with one of said windings, whilethe other winding is' connected to one of the thermostat members and tothe breaker spring which cooperates with the catch spring as described.

8. A fuse-plug type circuit breaker as defined in claim '7, furthercharacterized in that-a second lever is provided, one end being moved bythe movement of said lever-operating member, while the other end engagesthe breaker spring which cooperates with the breaker catch spring forthe purpose described.

9. A fuse-plug type circuit breaker as defined in claim 7, furthercharacterized in that the push button stem goes through an opening inthe catch spring and extends a length suiiicient to engage the otherbreaker spring to press it in a direction away from the catch spring asand for the purposes described.

10. A fuse-plug type circuit breaker as defined in claim '1, furthercharacterized in that the leveroperating member is in the form of anon-magnetic pin seated on the end of said core piece,

at least its end -6118181118 the catch lever being of insulatingmaterial.

11. A fuse-plug type circuit breaker as denned in claim '7,further'characterized in that the plug center" contact member is a tubepreferably nonmagnetic-,the-core piece being normally held by the catchlever at the contact end of the tube, while a' plug of magnetic materialis located in the upper end of the tube but leaving a substa'ntlal airgap between the plug and the core piece, and further characterized inthat a shell of magnetic material encloses said windings, said shellhaving a magnetic return member at the contact end of the plug.

12. A fuse-plug type circuit breaker to ilt standard fuse-plug socketsincluding a base of insulating material having a stem exteriorlycarrying a threaded contact shell and a removable cap of insulatingmaterial, a central contact for the plug comprising a tubular metallicmember, a core piece normally located in one end of said tubular member,a magnetic plug member positioned in the other end of the tubular memberleaving an air gap between it and the core piece, a magnetic returnshell within the inner wall of the stem and contacting with said plug, apair of differentially wound windings within the return shell, a plateof insulating material carried by the base above the stem, a pair ofbreaker springs on the plate having cooperative contacts, a levermounted on the plate and having a catch at one end to engage one of saidsprings, a pin extending through said plug member into cooperativeposition with the other end of said lever and said core piece, athermostat device carried on said plate and connected in circuit withone of said windings, the other of which is connected in shunt to thethermostat, while said catch spring is connected to said plug shellcontact, and a resetting button operatively attached to said catchspring and extending through the cap for setting said breaker.

13. A fuse-plug type circuit breaker as defined in claim 12, furthercharacterized in that a second lever is carried by said plate, one endof the lever engaging the second breaker spring, while the other end ofthe lever is moved by said pin as and for the purposes described.

14. A fuse-plug type circuit breaker to iit standard fuse-plug socketsincluding, a base and a removable cap, both of insulating material, aplate of insulating material on the base housed by the cap, a pair otbreaker springs having cooperative contacts, a setting device carried byone of the springs and extending through the cap, a thermostatdevicecarried on the plate, a pair of diilerentially wound windingslocated in the stem, a movable core piece located within the windings, alever having a catch at one end to engage said spring carrying thesetting device, an operating member engaging the other end of the leverand actuated by said core piece, said windings, breaker springs andthermostat device being connected to respond to the iiow of currentsubstantially as described.

15. A fuse-plug type circuit breaker as dened in claim 14, furthercharacterized in that said catch lever is carried on said plate and asecond lever is also carried on the plate, one end of the second leverengaging the other of said breaker springs, while the other end of thesecond lever is actuated by the movement of said operating member.

16. A fuse-plug type circuit breaker to fit standard fuse-plug socketsincluding, a base and a removable cap. both o! insulating material. eir-.cuit breaker springs housed within said cap. a lever i'or catching andholding one ot the springs in contact with the other, means extendingwithoutthecapiormovingsaidsprinzstoclosedposition. said base havin: astem carryins socketensasins contact members. a pair ot diiienntiallywound windings within the stem, a movable core piece located near theaxial center of the windings. means actuated by the core piece to movesaid lever to release said sprinl. a thermostat device within the base.the windinls. breaker springs and thermostat device bein: connected torespond to the iiow of current substantially as described.

' by the core piece.

JOHN GUBBLINGER.

